Offset Connection Channels in Fuel Cell Resin Frames
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Solution Overview
Problem
In fuel cells with internal manifold structures, the large area of metal separators required for fluid passages increases material costs and makes the fuel cell size larger due to stress concentration in thin resin frame portions, which can be damaged easily.
Innovation Solution
The fuel cell design includes a resin frame member with fluid passages and connection channels that are offset between adjacent cell units, preventing overlap and reducing stress concentration, allowing for thinner frames while maintaining strength and reducing overall size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of thin portions in resin frame members is increased to prevent damage and ensure strength, then the strength and reliability are improved, but the dimension of the fuel cell in the stacking direction becomes large
Solution Approach 1:
The invention transitions from a two-dimensional overlap pattern to a three-dimensional offset pattern by positioning connection channels at different heights (different z-coordinates) in adjacent cell units. This dimensional change allows the thin portions to be separated in the stacking direction, eliminating stress concentration while maintaining frame thickness within normal ranges and thus reducing the overall fuel cell dimension.
2Adaptability or versatility
If metal separators with large area are used to provide fluid passages, then the fluid passage functionality is improved, but the amount of expensive material increases and unit cost becomes high
Solution Approach 1:
The invention divides the fluid passage system into two functional components: connection channels formed in the resin frame members for inter-cell fluid transfer, and flow fields formed in the metal separators for intra-cell fluid distribution. This segmentation allows the metal separators to be smaller in area since they only need to handle flow field functions, while connection channel functions are distributed to the resin frame members, thus reducing the total quantity of expensive metal separator material required.
3Device complexity
If connection channels are overlapped in the stacking direction, then the structural simplicity is maintained, but stress concentration occurs and thin portions can be damaged easily
Solution Approach 1:
The invention introduces asymmetry in the positioning of connection channels between adjacent cell units by offsetting them in the stacking direction. Instead of symmetric overlap, the connection channels are positioned at different heights, creating an asymmetric distribution that eliminates stress concentration points while maintaining reasonable structural complexity through a systematic offset pattern.
Data Source
AI summary
A cell unit of a fuel cell includes a first membrane electrode assembly, a first metal separator, a second membrane electrode assembly, and a second metal separator. Resin frame members are provided at the outer ends of the first and second membrane electrode assemblies. Coolant connection channels including a plurality of grooves is formed in each of the resin frame members. The grooves of the coolant connection channels of the cell unit and grooves of coolant connection channels of a cell unit that is adjacent to the cell unit in the stacking direction are offset from each other, and are not overlapped with each other in the stacking direction.